Differential cellular immune response of Galleria mellonella to Actinobacillus pleuropneumoniae

Abstract

In the present work, we have investigate the cellular immune response of Galleria mellonella larvae against three strains of the gram-negative bacterium Actinobacillus pleuropneumoniae: low-virulence (780), high-virulence (1022) and the serotype 8 reference strain (R8). Prohemocytes, plasmatocytes, granulocytes, oenocytoids and spherulocytes were distinguished according to their size and morphology, their molecular markers and dye-staining properties and their role in the immune response. Total hemocyte count, differential hemocyte count, lysosome activity, autophagic response, cell viability and caspase-3 activation were determined in circulating hemocytes of naive and infected larvae. The presence of the autophagosome protein LC3 A/B within the circulating hemocytes of G. mellonella was dependent on and related to the infecting A. pleuropneumoniae strain and duration of infection. Hemocytes treated with the high-virulence strain expressed higher levels of LC3 A/B, whereas treatment with the low-virulence strain induced lower expression levels of this protein in the cells. Moreover, our results showed that apoptosis in circulating hemocytes of G. mellonella larvae after exposure to virulent bacterial strains occurred simultaneously with excessive cell death response induced by stress and subsequent caspase-3 activation.

Conidiobolus coronatus induces oxidative stress and autophagy response in Galleria mellonella larvae

“…In the present study, the level of NBR1 protein was found to be elevated in wax moth hemolymph after fungal invasion, while p62 protein level remained stable, even after infection (Fig 8); it is possible that autophagy took place without the need for p62 protein. Our results confirm those of previous studies showing that hemocytes of wax moth induce the autophagic pathway [44,57]. Further evidence that these two processes might interact and coincide with each other was given by Mizerska-Dudka and Andrejko (2014), who observed features typical for both apoptosis and autophagy in wax moth hemocytes following Pseudomonas aeruginosa infection.…”

Antimicrobial photodynamic therapy with phenothiazinium photosensitizers in non-vertebrate model Galleria mellonella infected with Fusarium keratoplasticum and Fusarium moniliforme

“…The numbers of colony-forming units (CFU) were counted after 48 h of incubation at 30ºC. The experiments were repeated twice and representative experiments are presented.The THC in the hemolymph of G. mellonella larvae were assayed using a protocol fromBlanco et al (2017). The experiment was performed with 3 larvae for each test condition.…”

Galleria mellonella as a Novelty in vivo Model of Host-Pathogen Interaction for Malassezia furfur CBS 1878 and Malassezia pachydermatis CBS 1879

“…It was observed that the percentage of plasmocytes tends to increase with respect to the other four hemocyte classes. This may be due to the fact that these cells are responsible for adherence and phagocytosis, which is the main antifungal immune response, and also that these cells participated in nodule formation (Arteaga Blanco et al, 2017;Boguś et al, 2018;Pereira et al, 2018).…”

“…The hemolymph drop was then spread over and stained with Wright's stain. According to previous reports (Arteaga Blanco et al, 2017;Wojda, 2017;Boguś et al, 2018), hemocytes were characterized and counted under a light Leica DM500 microscope.…”

“…Hemocyte population percentages were obtained and tabulated to characterize the immune response of G. mellonella and determine whether or not the infection of the two species of Malassezia has an effect on hemocyte populations. Cell classification was carried out based on size and morphology (Figure 4) (Arteaga Blanco et al, 2017;Wojda, 2017;Boguś et al, 2018). In both cases of M. furfur and M. pachydermatis infection assays at 33 or 37 • C, a significant difference was found between cell populations (p < 0.0001, 2-way ANOVA test).…”